Hi, been following the forum for a bit and find it to be a great source of information with many experts on board. I've actually demoed both the 2002/2003 X and XX recently at Mammoth, California so I figure I throw in my 2 cents.
I've been reading on this board that many favors the XX over the X because of versatility. I would have to agree with that but I still think the X is much more quicker edge-to-edge compared to to XX.
I demo'd the X back in Christmas where I was blissed with 2 feet of fresh powder over night. The X has decent float on the powder but not great. I initially was getting toss around a bit when the powder got chopped up because the X does not have heft and it's very lively. However, I adapted to the X's characteristics by doing fast, fall line turns on crud and then I was fine. The X is not good at plowing through messy snow, rather, it is very quick and nimble and can float or flow over the mess. I'm into short radius turns so I actually like it.
A couple of weeks ago I returned to Mammoth but this time it had firm snow. I rented the XX this time due to all the attention given in this forum. I like it as it carved well in groomed and handled well in the steeps. It was even fairly quick in the bumps. Unfortunately, I didn't have the opportunity to test it in pow or crud this time. I'm sure the XX excels over the X in these areas.
To give them a fair comparison, I demo'd the X again the next day in the same snow conditions. The X and XX actually skied fairly alike in the firm groomed and the steep, but when it comes to big moguls the X was much faster edge-to-edge than the XX. Hands down.
Since I am into honing my skills in the bumps right now, I went and picked up a pair of X. I guess it's all a matter of what you like to ski the most. Now I'm hearing great things about the B2 and that it's even quicker in the moguls... I gotta check it out!